Examinando por Autor "Martín Sómer, Miguel"

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Dynamic concentration factor: A novel parameter for the rigorous evaluation of solar compound parabolic collectors
(Elsevier, 2022-01-06) Martín Sómer, Miguel; Moreno San Segundo, José; Marugán, Javier
Solar-driven photoactivated processes have proven to be effective technologies for removing pathogens and chemical contaminants from water. Reflector systems are commonly used to concentrate the sunlight and improve their efficiency. Among them, compound parabolic collectors (CPC) are the most widely used, being the concentration factor (CF), their main design parameter, calculated directly from the geometry. This work presents the development of a novel parameter, called dynamic concentration factor (DCF), to assess the efficiency of a CPC as a function of the solar vector (the beam angle depends on location, season of the year and time of the day) and the reflective properties of the material. The DCF is defined as the ratio between the incident radiation reaching the receiver with and without the collector. DCF of CPC with different acceptance angles have been calculated with a ray-tracing tool and validated with experimental data from actinometry reactions. Analysis of the results has been done by plotting the dependence of the DCF versus the beam angle for increasing reflectivity indexes. This facilitates the estimation of the total radiation available to conduct a photoactivated process, whose reaction rate is proportional to the incident photons in the receiver. Global worldwide results using time-varying local solar irradiation data showed that, although the CPC with an acceptance angle of 90° (CF = 1) is commonly assumed as an optimal configuration due to its ability to concentrate diffuse radiation, the use of CPC with different acceptance angles could be more suitable in some regions of the planet.
Empleo de roles de conducta para mejorar el trabajo colaborativo en asignaturas del ámbito ingenieril
(Universidad San Jorge, 2024-01-01) Linares, María; Moreno, Inés; Orcajo, Gisela; Vizcaino, Arturo; Garcia, Alicia; Gomez, Gema; Martín Sómer, Miguel; Pariente, Isabel
Este artículo describe el desarrollo e implementación de un método para organizar el trabajo colaborativo en cursos de ingeniería, maximizando la participación y el aprendizaje en actividades grupales, aprovechando las fortalezas individuales de cada miembro del equipo. Se definen cuatro roles de comportamiento: líder, colaborador, reflexivo o creativo, que se asignan a cada estudiante de manera sencilla a través de un cuestionario que consta de 40 preguntas utilizando Microsoft Forms. Se han observado diferencias en los porcentajes de roles predominantes según el curso y el nivel de estudios en los que se implementa esta metodología. Los estudios más técnicos tienden a tener una mayor proporción de líderes, y a medida que los estudiantes avanzan en sus estudios, las proporciones tienden a igualarse. Finalmente, se destaca que esta metodología ha sido bien valorada por los estudiantes, obteniendo resultados académicos superiores en comparación con actividades grupales anteriores con grupos aleatorios. This article presents the development and implementation of a method for organizing collaborative work in engineering courses. The method aims to maximize participation and learning in group activities by leveraging the individual strengths of each team member. Four behavioral roles - leader, collaborator, reflective, and creative - are defined and assigned to each student through a straightforward questionnaire consisting of 40 questions, utilizing Microsoft Forms. Differences in the predominant role percentages have been observed based on the course and educational level where this methodology is applied. More technically oriented programs tend to have a higher proportion of leaders, while as students’ progress in their studies, the proportions tend to equalize. Notably, this methodology has received positive feedback from students and has yielded superior academic outcomes compared to previous group activities with randomly formed groups.
Optimización de reactores fotocatalíticos para el tratamiento de aguas: fuente de iluminación, configuración y tipo de catalizador
(Universidad Rey Juan Carlos, 2019) Martín Sómer, Miguel
Nowadays, the protection of the environment stands out as one of the main problems of modern societies with great social, political, technological and economic repercussion. The growth of the population and the expansion of numerous agricultural and industrial activities have led to the necessity of implementing a strict environmental legislation that regulates the quality of the main effluents generated for its discharge in municipal collectors or directly to the environment. Water availability is increasingly scarce, and insufficient natural water resources in arid and semi-arid zones constitute a serious problem for the population settled in them. In European countries, 54% of total water consumption is for industrial use, according to the UNESCO report "Water for all, Water for life"1. Part of the water is discharged after being used, containing waste resulting from the production process. Therefore, industrial wastewater has particular characteristics depending on its origin, which determines its treatment before being discharged into the natural environment. Contamination of surface waters with chemical agents represents a threat to the aquatic environment since, in some cases, this type of contamination has effects such as acute and chronic toxicity to aquatic organisms, accumulation in the ecosystem and loss of habitats and biodiversity, as well as damage to human health.
Short-term fouling control by cyclic aeration in membrane bioreactors for cosmetic wastewater treatment.
(Elsevier, 2015-12-01) Monsalvo, Victor; Lopez, Jesus; Martín Sómer, Miguel; Fernandez Mohedano, Ángel; Rodriguez, Juan José
Air sparging is extensively used to mitigate membrane fouling in membrane bioreactors (MBRs), which represents an important operation cost in submerged MBR. In this work, the effect of intermittent aeration mode on the membrane fouling has been studied by analysing the influence of the aeration cycle duration in a submerged MBR treating cosmetic wastewater. The long-term filtration at a permeate flux of 8.0 L m−2 h−1 and a constant specific air demand (SAD) of 1.5 m3 m−2 h−1 led to a significant increase in the transmembrane pressure (TMP) after 10 d. The tangential shear showed a limited effect on preventing the deposition of small particles, since carbohydrates and proteins present in the fouling layer were mainly smaller than 1 μm. Flocs showed a low stability under shear stress, which limits the increase in the SAD to avoid undesirable effects over the mixed liquor permeability. The intermittent aeration operation allowed the operation of the MBR under low aeration intensity (low SAD) without compromizing the fouling of the membranes. The use of aeration cycles shorter than 1 min led to an efficient control of fouling, which resulted in a negligible increase in the TMP after 2 h, operating at a permeate flux of 12.0 L m−2 h−1.
State of the art review of photocatalytic water treatment
(University of Georgia Publishing House, 2023-03-30) Abdelaal, Ahmed; Banei, Farzin; Fenti, Angelo; Maryam , Nili Ahmadababdi; Martín Sómer, Miguel
Supplying clean water is a significant problem in contemporary societies. The rise of industrialization and urbanization, coupled with population growth have caused a shortage of clean water supplies, and the disparity between pure water demand and availability is expected to worsen. For this reason, the need to treat water impacted by emergent organic contaminants (EOCs) and inorganic pollutants has become a primary worldwide concern. The most promising approach for water treatment is the use of primary photocatalytic oxidation processes. The paper begins by outlining the issue of scarce water supplies and the many methods of purification, including photocatalysis using semiconductors like metal oxides, graphene oxides, and MOFs. Moreover, the articles also review published research on the application of these photocatalysts materials for the degradation of pollutants from water. Finally, the article provides an overview of photocatalytic water treatment technology, discussing the basic mechanism of photocatalysis and nanobased photocatalysts used for the degradation of organic pollutants in water and wastewater.
Wavelength synergistic effects in continuous flow-through water disinfection systems
(Elsevier, 2023-12-01) Pai Uppinakudru, Adithya; Martín Sómer, Miguel; Reynolds, Ken; Stanley, Simon; Bautista, Luis Fernando; Pablos, Cristina; Marugán, Javier
The past decade's development of UV LEDs has fueled significant research in water disinfection, with widespread debate surrounding the potential synergies of multiple UV wavelengths. This study analyses the use of three UV sources (265, 275, and 310 nm) on the inactivation of Escherichia coli bacteria in two water matrixes. At maximum intensity in wastewater, individual inactivation experiments in a single pass set-up (Flow rate = 2 L min−1, Residence time = 0.75 s) confirmed the 265 nm light source to be the most effective (2.2 ± 0.2 log units), while the 310 nm led to the lowest inactivation rate (0.0003 ± 7.03 10−5 log units). When a combination of the three wavelengths was used, an average log reduction of 4.4 ± 0.2 was observed in wastewater. For combinations of 265 and 275 nm, the average log reductions were similar to the sum of individual log reductions. For combinations involving the use of 310 nm, a potential synergistic effect was investigated by the use of robust statistical analysis techniques. It is concluded that combinations of 310 nm with 265 nm or 275 nm devices, in sequential and simultaneous mode, present a significant synergy at both intensities due to the emission spectra of the selected LEDs, ensuring the possibility of two inactivation mechanisms. Finally, the electrical energy per order of inactivation found the three-wavelength combination to be the most energy efficient (0.39 ± 0.05, 0.36 ± 0.01 kWh m−3, at 50% and 100% dose, respectively, in wastewater) among the synergistic combinations.